The GMC CCKW

i am looking for any information on 1 1/2 ton Internetional harvester. I know my truck is rare but I can't image it being so rare I can';r fiund any info on it. I amn looking for manuals. and teck info. If you know anything about them, please contact me.,

Here is a veiw of the engine. I suspect IH used these in many of their vehicles but I need info on it to find any type of manual. Any help or ideas would be appreciated
Denny